Process of curing tires and the like



June 2, 1931. H. R. MINOR PROCESS OF CURING TIRES AND THE LIKE FiledJune 24. 1927 Y maintain pressure.

'tion of air used leaked out into the heaters -curlng stage this fore,prefer to use steam as Patented June 1931 HENRY B. MINOR, 0F OSSINING,NEW YORK,

THE LIQUID CARBONIO CORPORATIO ASSIGNOR, BY MESN'E ASSIGNMENTS, T0 N, ACORPORATION 0F DELAWARE PROCESS 0F CURING TIRES ANI) THE LIKEApplication inea :rune 24,

This invention relates to animpr'oved process of curing rubber tires andthe like, and it includes the steps of bringing up the initial pressureinair-bags with a gaseous medium and then maintaining said pressure byanother gaseous medium while curing is eiiected that'is to say by myprocess, I bring up the pressure in air bags by an initial pressure gasand maintain said pressure by another gas or ga-seous mixture which isless expensive than the initial pressure gas.

In the art of curing rubber tires, it has heretofore been the practiceto fill the air bags with about a quart of glycerine and then use air asa pressure means, both initially and during the regress of the cure toecause a large proporand settled at the bottom thereof, a certainpercentage of tires would come out improperly cured even when agitatorswere used to overcome the said disadvantages.

In my earlier investigations, I used carbon dioxide (CO2) as a Apressuremeans to bring up and maintain the pressure in air bags with excellentresults. Because, however, of the large losses of this expensive gasduring thel process was expensive, I accordingly devised a method ofmaintaining the pressure in air bags with a cheaper gas, as air, steamerthe like, after said pressure was brought up with carbon dioxide. Iprefer to use as the pressure maintaining agent a moisture supplyingmedium and I .found high pressure steam either with or without an inertgas to ive very good results. A small proportion 0I air with the steamapparently produces no ill eii'ects. Steam is cheaper than compressedair, and I, therethe primary pressure maintaining medium after thepressure has been brought up bythe selected initial pressure producingga s.

As an examp e of a preferred form of carrying out my improve process Iuse carbon dioxide either alone or in combination with other inert gasesfor the initial pressure gas to bring up the pressure in air bags forthe purpose of curing rubber tires or other rubber goods.

gases, as nitrogen or flue 1927. Serial No. 201,037.

As soon as the desired pressure has been reached, carbon dioxide orother inert gas, if used, is shutoff and pressure is maintained by highpressure steam either without or with a small proportion of an` inertvgas. Pressure is thus maintained until cure is effected. When steam isused as the pressure maintaining medium it is shut oil at the end of thecure and a small portion of the steam may be returned with the carbondioxide to the gasometer, where, b condensation, it will be separatedfrom the carbon dioxide which is then ready for reuse. Obviouslymixtures of steam with other inert gases as ue gases or otherinexpensive gases'may be vused as the pressure maintaining medium.

In order to carry out my new and improved process'any suitable apparatuswill serve and'for the purpose of illustration, I have shown adiagrammatic representation of an apparat-us Suited for process.

In the accompanying drawings,

Figure 1 is a view in elevation of apparatus suited for carrying out' myinvention, andv Figure 2 is a view showing connections of the gas supplyand gas returning means at the vulcanizer.

In said drawings, I have indicated at 10 a. .CO2 supplywhich isconnected to the gasometer 22 and the compressor 11 by a conduits 12 forsupply CO2 or other initial pressure gas. A pressure line 14 connectsthe 'compressor through an expansion tank 16 and conduits 17 and 18. Thecut off valves l9and 2O permit control of CO2 or other pressure mediumto or from the vulcanizer as valves 19 and 2O respectively are openedand closed. A return l conduit 21 returns the used CO2 and some of thesteam to the gasometer 22 where the steam condenses as stated above.When high pressuresteam is used it is admitted through conduit 30, valve31, to the vulcanizer and pressure is thereby maintained. By openingvalve 32 in conduit 33 the pressure maintaining `medium may bereleasedto the desired extent. Valve 32 is then closed and valve practicing my-11 to the vulcanizer 15, V85.

20 is opened for returning the initial pressure gas to the gasometer.

From the above apparatus, it will be clear that CO2 or the like may besupplied to the 5 vulcanizer'under suilicient pressure to bring up saidpressure in the air ba s within the vulcanizer. Valve 19 is then c osedand the inlet valve 31 for admission of steam or other pressuremaintaining medium is then opened to admit the saine at high pressurefor backing up the CO2 under pressure. After curing has been effectedthe valve 31 is closed and I the CO2 valve 2O o en for the return of theCO2 with some of t e steam to the gasometer in the manner and Jfor thepurposes stated. While steam is preferred for the best results andbecause of its low cost any other fluid may be used for backing theinitial pressure of the beneficial gas.

20, Having now described my invention, what I claim as new and useful,and desire to secure by Letters Patent is 1. The method of curing rubberarticles which comprises placing an expansible bag ad'acent saidarticles then causing pressure to e produced in sai bag by carbondioxide gas and backing said medium by a heated condensib'legas tomaintain said pressure during the curing action,

2..'l`he method of curing rubber articles which comprises placing1 anexpansible bag adjacent said articles, t en filling said bag 'withcarbon dioxide to produce initial pressure and backing up said initialpressure by steam.

` 3. That method of curing rubber tires with aid of air bags underpressure which consists in bringing up the initial pressure of air bagswith carbon dioxide and backing said 40 pressure `with steam.

4. That method of curing rubber tires with aid of air bags underIpressure which consists in bringing up thefinitial pressure of airbags, with carbon dioxide and backin said pressure with steam, thencausing sai carbon dioxide and a portion of the steam to be returned toa gasometer.

5. That method of curing rubbeitires with aid of air bags under ressurewhich 4consists 5 in bringing u the initial pressure of air bags withcar on dioxide and backing up said 'pressure with steam and an inertgaseous medium. y p

6. That method of maintaining an'expansible v'ulcanizing pressure bag incondition for curing rubber articles, which comprises using an inert aslto bring upv the pressure ingsaid bag an maintaining said pressure bysteam. v

0 n testimony whereof I havehereunto setin hand on this 20thday of June,A.. D.

- t HENiiYaMiNoR.-

